Most material available has poorly preserved flowers which perhaps explains the original description of the pollinia as pendulous. Reexamination of paratype material with quite well-dried
flowers has shown that they are horizontal. There is little, apart from fruit morphology, to distinguish Merrillanthus from Tylophora, especially T. augustiniana, which differs only by the
laxer inflorescences and much smaller flowers (its fruits are not known).